1. Field of the Invention
The present invention generally relates to coordinate input devices, and more particularly to a coordinate input device that is capable of performing a three-dimensional input without a special operation space.
2. Description of the Related Art
As input means of computers, besides keyboards, pointing devices are very popular because of good operation thereof. For example, the pointing devices such as a mouse, digitizer and the like are suitable for desk-top computers.
In recent years, with the spread of notebook computers that are suitable to use in outdoors or in cars, it brings about a problem that the mouse, the digitizer and the like that need a special operation space become inconvenient for use of the note-book computers.
In order to solve the above-mentioned problem, conventionally, a pointing device is developed that is capable of detecting an inclination angle by inclining an operation portion thereof.
A description of such a conventional pointing device is given below with reference to FIGS. 1 through 4.
Reference numeral 1 represents the conventional pointing device, which comprises an operation portion 2, a pressing portion 3 and a coordinate detection portion 4.
The operation portion 2 includes a key top 2a, a stick 2b and a semi-spherical holder 2c. As can be seen from FIG. 1, the stick 2b consists of a cylindrical portion 2b-1, a semi-spherical portion 2b-2 and a protruding portion 2b-3. The cylindrical portion 2b-1 has one end fixed in the key top 2a and the other end formed integrally with the semi-spherical portion 2b-2. The semi-spherical portion 2b-2 and the semi-spherical holder 2c are joined together to form a sphere. The protruding portion 2b-3 protrudes sidewise from the bottom portion of the semi-spherical portion 2b-2.
Further, the operation portion 2 has the semi-spherical portion 2b-2 accommodated in a container consisting of an upper cover 5a and a housing 5b. The upper cover 5a has a central opening 5a-1. The housing 5b has an upward-projecting portion 5b-1 and a concave portion 5b-2 formed on the upward-projecting portion 5b-1. The semi-spherical portion 2b-2 is engaged with the opening 5a-1 of the upper cover 5a, and the semi-spherical portion 2c is supported by the concave portion 5b-2.
The pressing portion 3 consists of a cylindrical slider 3a and a coil spring 3b. The cylindrical slider 3a is configured to be slidable along a side wall 5a-2 of the upper cover 5a. The coil spring 3b has its two ends fixed between the upper cover 5a and the bottom of a concave portion 3a-1 formed in the slider 3a so as to be able to force the slider 3a all the time. The slider 3a has a protruding portion 3a-2 extended toward and around the semi-spherical portion 2b-2 and engaged with the protruding portion 2b-3.
The coordinate detection portion 4 includes a magnet 4a, which is provided within the holder 2c, and four magnetoelectric devices 4b, which are loaded on a printed substrate 6 joined to the bottom of the housing 5b. In addition, as can be seen from FIG. 3, the four magnetoelectric devices 4b are arranged symmetrically with respect to the central axis of the magnet 4a. 
According to the previously described configuration of the pointing device 1, by manually operating the key top 2a, the slider 3a is moved upward against the coil spring 3b, and thereby the stick 2b can be inclined to any direction as shown in FIG. 2. At the same time, the magnet 4a mounted within the holder 2c becomes inclined to the magnetoelectric devices 4b fixed on the printed substrate 6.
Next, a description is given below with respect to the principle of how the pointing device 1 detects a coordinate.
In the case where the stick 2b is stood vertically to the printed substrate 6 as shown in FIG. 1, the magnet 4a becomes symmetrically separate from the four magnetoelectric devices 4b (4b-1 through 4b-4 in FIG. 3) as shown by a solid line in FIG. 4. Therefore, magnetic fields applied to the respective magnetoelectric devices 4b-1 through 4b-4 become equal. For example, if a magnetic-field-sensitive direction for detecting the magnetic fields of the magnetoelectric devices 4b-1 through 4b-4 becomes vertical to the printed substrate 6, then magnetic-field-sensitive-direction components B1 through B4 of magnetic flux passing through the magnetoelectric devices 4b-1 through 4b-4 become approximately equal, and output voltages of the magnetoelectric devices 4b-1 through 4b-4 become approximately equal as well.
On the other hand, in the case where the stick 2b is inclined to the printed substrate 6 as shown in FIG. 2, the magnet 4a becomes non-symmetrically separate from the four magnetoelectric devices 4b-1 through 4b-4 as shown by a broken line in FIG. 4. At this time, if the magnet 4a farther approaches to the magnetoelectric device 4b-1 and farther separates from the magnetoelectric device 4b-3, the component B1 becomes larger than the component B3 and in response to this, the output voltages of the magnetoelectric devices 4b-1 and 4b-3 are changed. By calculating an output difference between the magnetoelectric devices 4b-1 and 4b-3, a magnetic inclination xcex8 can be obtained and converted into an X coordinate value for moving a cursor in a display (coordinate space). Similarly, by calculating an output difference between the magnetoelectric devices 4b-2 and 4b-4, a magnetic inclination xcex8 can be obtained and converted into a Y coordinate value.
In other words, whenever the stick 2b is inclined to a direction, an XY coordinate value can be obtained corresponding to the inclined direction or an angle thereof. Accordingly, the thus-obtained XY coordinate value may be inputted into a computer which decides a moving direction, a moving distance and a moving speed of a cursor based on the YX coordinated value so as to display the cursor on a display of thereof.
The conventional pointing device 1, however, is available only for the two dimensional coordinate input in the XY directions but cannot detect information in a Z coordinate direction. As a result, the conventional pointing device 1 cannot perform a three-dimensional coordinate input system that is increasingly required by various complicated software applications.
It is a general object of the present invention to provide a coordinate input device, in which the above disadvantages are eliminated.
Another and a more specific object of the present invention is to provide a three-dimensional coordinate input device comprising a magnet; a plurality of magnetoelectric elements disposed facing toward the magnet, for generating a first signal detecting an X coordinate value and a second signal detecting a Y coordinated value when the magnet is inclined to the magnetoelectric elements, and for generating a third signal for indicating a Z coordinate value when the magnet is moved vertically to the magnetoelectric elements; and a signal processing portion for processing the first signal, the second signal and the third signal so as to determine an XYZ coordinate value to be displayed on a coordinate space.
Still another object of the present invention is to provide a three-dimensional coordinate input device for indicating a predetermined coordinate point on a coordinate space, comprising an accommodating portion; an operation portion having a build-in magnet; a plurality of magnetoelectric elements; and an elastic member; wherein the accommodating portion includes a substrate serving as a bottom thereof and a case formed integrally with the substrate and having an opening through which the operation portion is moved up and down; the operation portion includes a flat bottom and a projection formed around an outer periphery near to the bottom; the plurality of magnetoelectric elements include four magnetoelectric elements, which are provided on the substrate and are approximately symmetrical with respect to an intersection of the substrate and a magnetic field direction generated from at least one magnetic pole center of the magnet; the elastic member includes a first elastic member engaged between the projection of the operation portion and the substrate, and a second elastic member, stronger than the first elastic member, engaged between the substrate and an approximately semi-sphere which has a curve top surface contacting the bottom of the operation portion and a bottom smaller than the bottom of the operation portion; the operation portion is inclinable and vertically movable, the first elastic member being inclinable during the inclination of the operation portion, the second elastic member being vertically movable during the vertical movement of the operation portion; and an XYZ coordinate point is indicated on the coordinate space based on output voltage variations of the magnetoelectric elements caused by inclining and vertically moving the operation portion.
Other objects, features and advantages of the present invention will become more apparent from the following detailed description when read in conjunction with the accompanying drawings.